You’ve most likely found yourself here after receiving a “Service 4WD System” error after trying to engage 4low or attempting to set your transfer case into neutral for recreational towing. If you find yourself here because you are thinking of having the N23 recall done…read this fully first.

(Input and corrections welcome and I’ll edit as needed. Hope this post will be an alternative to the now ungainly 4500+ post main N23 tread as well as many others on this topic.)

This was prompted after reports of vehicles shifting into neutral and rolling away while using the remote start feature. Several injury accidents involving this problem were reported.

The investigation found that during the initial vehicle startup sequence, the controller can automatically command a transfer case shift, without input form the driver. The defect notice referenced the warranty analysis that was completed on Oct 11, 2012 found that cracks in the tracings on the circuit board of the transfer case actuator resulted in a biased (offset) position signal which could be incorrectly interpreted by the final driver controller module (FDCM) and cause this unexpected shift into neutral.

Rather than replacing the transfer case actuator with the problematic circuit board, a re-programming (flash) of the FDCM would be performed to prevent this unexpected neutral shift while starting.

Starting shortly thereafter, owners began reporting loss of 4low/neutral function (neutral setting of the transfer case rather than the transmission) and would get a “Service 4WD System” error when attempted. The error would clear upon restart but returned each time 4low/neutral was attempted.

When returned to the dealer for repair, owners were (and still are) met with “You’re the first one that I’ve seen with this problem” or “This is in no way connected to the recall”. When confronted with the growing number of owners reporting the problem, Chrysler’s official response was “Chrysler Group is assuming the cost of repairs, on a case-by-case basis, for certain customers who observed warning lights in their instrument clusters following completion of a recall-related software update. However, the update has no bearing on the root cause of the warning-light activation. Chrysler Group engineers developed the software update, which prevents an inadvertent transfer-case shift and also enables identification of a pre-existing electrical fault that was previously undetectable”.

Not telling owners that the “previously undetectable” fault was the bad circuit board in the actuator that caused the recall in the first place. (Reported here by Graham Kozak and the fine folks at Autoweek who kindly posted our tail. http://autoweek.com/article/car-news...-chrysler-says )

Chrysler even went so far as to command Lee, their jeepforum.com representative at the time (JeepCares), to go dark on the subject. Guessing she was being too honest with forum members as to N23. Lee has since retired after 30 years of service. I’m hopeful that the current JeepCares can get permission to once again assist owners with N23 problems as the Chrysler’s rep on this forum should.

It was a gloomy time for WK/XK owners. Dealers were still saying there was no connection, Chrysler had no solution but dealers, without other options, were still charging owners for expensive repairs that may work for weeks or months…. but then the dreaded “Service 4WD System” error would return.

RV owners were facing angry faces in their rear view mirrors after telling their wives that they would have to drive their Jeep the 1000 miles back home separately because they couldn’t put it in neutral to flat tow.

“This is my last Jeep!” and “I’ll never by a Chrysler product again!!” was shouted from garages around the world. Fiat was confirmed as a four letter word. I am still flummoxed by how badly Chrysler/Fiat as a company has and still is handling this subject. Sure their sales are still strong as is true in all of the auto industry, but this type of poor customer service will surely come back to haunt them.

But back to our story.

Our more tech savvy users (Blown7 among them) found that the FDCM expects a certain voltage signal from the actuator to instigate a particular shift. But the N23 program set the voltage tolerance so close that even good actuators would report C140F “Transfer Case Range Position Sensor Erratic Performance” errors. For a time Blown7 could have made a full time job out of returning FDCM’s to their pre-N23 programming. Frankly I was surprised that a voltage level signal is used to control function rather than a digital signal. So oddly analog.

Owners left to their own devises found that unplugging the Final Drive Control Module (FDCM) found under the rear/center seat, starting the vehicle and reconnecting would reset the FDCM and return 4low/neutral function for a time but had to be repeated when the error returned.

It was then found that just popping the hood pulling the fuse to the FDCM (#25 for 05-07 & #33 for 08-10), starting the vehicle and moving a few feet forward then backward and replacing the fuse also reset the system and returned function. But this is also a temporary fix and must be repeated when the error returns weeks or months later. Good write up on the “Fuse Pull Trick” by Troy123 here http://www.jeepforum.com/forum/f67/n...l#post20486321

Owners with programming units like Flashpaq etc. also found they could clear the error codes to regain 4low function but also a temporary fix that had to be repeated.

Some owners found that even these temporary fixes stopped working after a certain number of tries.

A more permanent fix was found by replacing the FDCM with a salvage unit from a vehicle that had not had the recall done. Obviously the supply of these “pre-N23” FDCM units is limited and became very hard to come by. If you are looking at finding a pre-N23 FDCM your best bet is to pull your rear seat and get the number off of your current unit. The number will end in 199A* for QDII and 129A* for QT. “*” is the software version. You want one with a matching letter or one letter later for error free operation (i.e. if the original unit is a 199AK, either 199AK or 199AL will work) . http://car-part.com/ is a good place to start looking. Other software versions may work but display various error codes. Aside from a matching part number, you will need the VIN of the donor vehicle so you can check if the recall has been done. Do so by using plugging in the VIN here http://www.moparownerconnect.com/oc/...allsQuery.aspx If the N23 recall has not been done, it will show as outstanding. This solution does has the con of the unexpected neutral shift for owners that use remote start is a possibility. Also, you should swap out for your pre-N23 FDCM with the N23 affected one if taking in for any dealer work as they may try and re-flash your pre-N23 unit if left in the vehicle. Even for an oil change. Some owners go so far as to install a lock on their OBDII connection to prevent a re-flash of their pre-N23 FDCM.

(if Meeker Extreme is a forum member, thank you for the vid). Note: On a WK, the bolts holding the seat down are very hard to remove due to Locktite or such but other than that, a very straight forward swap.

While still not admitting to either dealers or owners the connection between N23 and the “Service 4WD System” error, on July 29th, 2014 a revised procedure was issued. http://www.wkjeeps.com/TSB/tsb_wk_2102214a.pdf . It stressed that the procedure was to be followed to the letter including connecting to a stable outside power source and repeated clearing of the error until it did not return. However if the C140F error can’t be cleared, the actuator has the cracked tracing on its circuit board and should be replaced. As part of this update however, dealers could no longer replace actuators under warranty/recall without the owner going through Chrysler’s customer service STAR case process in order to control costs.

OK. Now for the good news. The 7/29 re-flash seems to work for most owners impacted by the N23 recall. For those where it doesn’t and the C140F error can’t be cleared, actuator replacement is needed. No reports to date of any failures after the both the 7/29 flash and new actuator so this seems to solve the N23 problem.

Now for the bad news. Many dealers are still telling owners that there is no connection between the Service 4WD System error and N23 and charging unknowing owners $800+ to replace actuators or even to perform the re-flash under the 7/29 procedure. Both should be no charge under this recall.

If you have a N23 problem and taking your Jeep in for the 7/29 re-flash, take a copy of the 7/29 recall with you when you go in and ask it be followed exactly. I’m sure that many initial problems where due to the recall not being applied correctly. As long as the problem is connected to N23 (i.e. the C140F error) the flash should be no charge. Call Chrysler customer service from the dealer if they try to charge you for the flash.

Our new JeepCares (Thanks for the input!) recommends that your Service Manager be notified and if needed the dealership can use their internal technical escalation process and reference TSB: 21-022-14 REV. A SUBJECT: 4WD Lamp Illuminated and Diagnostic Trouble Code C140F Active in Final Drive Control Modules (FDCM) Memory. You can try this but you may still have to go through the STAR case process.

If the C140F error can’t be cleared with the 7/29 procedure after repeated tries, the harnesses/plugs etc. have been checked and actuator replacement is then recommended by your dealer and the dealer can't resolve using their internal technical escalation process, you will need to call Chrysler customer service to open up a STAR case to get the actuator replacement covered. Have the name of your dealer, service manager and your VIN on hand. First calls to Chrysler customer service are still being met with an initial level of trained denial. They’ll make a show of “helping” but if you are out of warranty, they will say there is nothing they can do for you. Owners must be insistent (but civil) and repeat and repeat that “The N23 recall was due to cracked tracing in the actuator’s circuit board as per the finding letter dated 6/13/13 so it is most certainly connected to the N23 procedure and actuator replacement should be covered under this recall” You broke it, you fix it. Then ask to speak to a supervisor. Remember to get and save your STAR number.

Do not expect approval or even to talk to a supervisor on your first call. You will get what they call a “24 hour call back”. They will call you back within that timeframe confirm a few things, then call the dealer to verify that all diagnostics have been done before they will OK. Then expect 3-4 months to pass before your actuator is available as they are on still on major backorder. Just keep following up with both your dealer and customer service until it gets in.

Just be nice to your dealer as you will need their cooperation for actuator replacement if needed and I’m very doubtful that the reimbursement under recall even comes close to the work needed. Its not that the actuator replacement is difficult but the troubleshooting can be labor intensive.

Now this part I don’t know about but if you have already paid for an actuator you may be able to get reimbursed. At a minimum you would need a dealer invoice showing the C140F as the reason the actuator was needed. Long shot I would think but worth a few phone calls.

But please keep in mind that not all “Service 4WD System” errors are due to N23. The N23 symptom is pretty specific in that the error only happens when 4low/neutral is tried and clears upon restart. Wheel speed sensors are still a good bet if N23 is not involved and clutch packs still wear out and harnesses fray. Only vehicles giving the C140F error are N23 bitten.

I took my 2005 WK back to the dealership last week to fix my N23 no 4low issue with the 7/29 update.

The dealership I took it to is the largest Jeep dealership in the state (by far) and they have several locations spread out in different cities. I took mine to their main facility with the 7/29 TSB in hand and to my surprise, I was the very first person to have the "No 4Low" problem and it was the very first time anyone there had seen the 7/29 TSB! Aw shucks. Really?

Before I had even finished explaining my issue and what I had done or needed them to do... I was told three times (yes, three) that they could perform the flash (at their cost) but if that didn't fix the problem, I would then be billed for the diagnostic and from then on.

I showed them the part on the TSB that says my problem was a result of the N23 recall, and he responded that he hadn't seen that part. I then whipped out "The Letter" and showed him where Chrysler admits the problem was caused by a cracked actuator board etc., and again he wasn't aware of anything and reaffirmed that they "couldn't do anything" without billing for the diagnostic, and that they "would have to talk to Chrysler" before they would touch it beyond the reflash.

I was pissed to say the least at how they had handled it up to that point so I handed the guy the TSB and the letter and told him to fix it and to do what ever he needed to do to make it happen, and that I wasn't paying a dime for what Chrysler broke. He could tell I was pissed so he took it back and had it reprogrammed and told me there were no codes and 4Low was now functional. No word or any direction whatsoever about what I needed to do if anything else occurs or if the code returns; I was just given my keys back and swiftly ushered out the door.

So far the TSB has held and my 4Low is still operational but it is worrisome that jeep is still treating their customers this way and playing ignorant about the issue all together.

[SIZE="3"]You’ve most likely found yourself here after receiving a “Service 4WD System” error after trying to engage 4low or attempting to set your transfer case into neutral for recreational towing. If you find yourself here because you are thinking of having the N23 recall done…read this fully first.

Nice write-up to summarize the longest thread in history. Would still be great to see FC exposed on Dateline or 20/20.

FWIW, for me, N23 affected full time 4wd as well. When driving around in snow/ice, anytime the rear started slipping, "Service 4WD" would flash up, and then go away. No chime. Result was no power getting to front axle, causing the Jeep to try and swap ends and spin out. This led me to try 4 Lo, where I again got Service 4wd, which led me to the fuse pull/reset. This made the QDII Jeep pretty much RWD only in low traction situations. 360 hp RWD, when I'm used to locking 4wd, not fun.

Ever since doing the fuse pull/reset, no more Service 4WD in full time 4 hi or 4 lo, and no more trying to swap ends.

FWIW, for me, N23 affected full time 4wd as well. When driving around in snow/ice, anytime the rear started slipping, "Service 4WD" would flash up, and then go away. No chime. Result was no power getting to front axle, causing the Jeep to try and swap ends and spin out. This led me to try 4 Lo, where I again got Service 4wd, which led me to the fuse pull/reset. This made the QDII Jeep pretty much RWD only in low traction situations. 360 hp RWD, when I'm used to locking 4wd, not fun.

Ever since doing the fuse pull/reset, no more Service 4WD in full time 4 hi or 4 lo, and no more trying to swap ends.

I recall only one other report of an owner that was having 4high problems after N23. Knowing the error code(s) its tossing would interesting to get an idea if its N23 related but sounds like the clutch packs were pretty much disengaged so no power was being transferred to the front rather than a transfer case shift position problem. Wonder if the front sensors were having a bad day but reset when you did the fuse trick.

Happen to be into any mud recently? How many miles? Wonder how your clutch packs are. Sounds odd...but how's your battery? Codes would tell.

What it seemed like is that right rear wheel would spin, then rear diff locks, then left and right rears both spin. Nothing to front. Rear tries kick out like a camaro in the snow.

I'm wondering if it might not be as a big a deal on QTII Jeeps because they become similar to QTI when the transfer case clutch doesn't lockup. The rears spin, btcs kicks in, power can go to the front axle.

QDII seems to be setup to lock the rear diff, then lock the TC. If no transfer case lock, then its an open center diff, and more or less RWD locker.

In relation to the 129a* or 199a* FDCM, mine has 713aa number. I can't seem to find what the differences are. The parts department ran my vin and tells me I have a Quadratrac II system not a Quadradrive II, and the 713AA is my original part. I purchased a 199AK unflashed. Does anyone know if this will be a problem?

Getting the 713AA right off the FDCM under my back seat. dealer Parts department confirmed from my VIN.

I went to the link, Printed my info and sure enough it is a QT2. Also got one from the dealer. It also says I have a front and rear LS Diff. I was under the impression the QT2 didn't come with this. Dealer is trying to charge $800 to replace it. Parts dept. will sell one for $234. When I inquired why the extra $500 for them to install it when you don't even need a screwdrive to swap it out they told me it had to be programed. From everything mentioned here and others swapping them out, no one has mentioned programing one.

So now I have 1 dealer saying the actuator is bad and needs replacing, and another dealer saying the FDCM is bad. Neither one says what the other says is wrong.

Also contacted Jeep Customer Care to open a Star case and they told me I had to do it at the dealer.

Getting the 713AA right off the FDCM under my back seat. dealer Parts department confirmed from my VIN.

I went to the link, Printed my info and sure enough it is a QT2. Also got one from the dealer. It also says I have a front and rear LS Diff. I was under the impression the QT2 didn't come with this. Dealer is trying to charge $800 to replace it. Parts dept. will sell one for $234. When I inquired why the extra $500 for them to install it when you don't even need a screwdrive to swap it out they told me it had to be programed. From everything mentioned here and others swapping them out, no one has mentioned programing one.

So now I have 1 dealer saying the actuator is bad and needs replacing, and another dealer saying the FDCM is bad. Neither one says what the other says is wrong.

Also contacted Jeep Customer Care to open a Star case and they told me I had to do it at the dealer.

Geeesss the beat goes on

Sad to hear that Chrysler has not updated their song.

Look through the invoices you've received from the two dealers and see if they give any error codes. You see C140F anywhere?

Okay here is the main question, I am considering getting a new FDCM with Part Number 713AA from Jeep, since they seem to be the only ones to have one. Does anyone know if it needs to be programmed or can I just install it my self???